You wrote:

> This risk functions as a guarantee.

Except it doesn't, particularly as far as lawyers are concerned. There are almost a million and a half active attorneys in the US. Just 500-600 are disbarred every year, and almost always for money-related violations, not bad advice. Public discipline is also relatively uncommon (about a quarter of 1% of attorneys every year) and usually related to issues like financial impropriety, neglect, undisclosed conflicts of interest and failure to communicate, not disagreement over the quality of advice.

If a lawyer drafts an agreement that causes a loss, a bar complaint will not help you recover your money. You'd need to sue for malpractice. This costs a lot of money and takes a lot of time. Because you're going up against a lawyer, expect the defense to be vigorous, especially, ironically, if you hired an attorney at a good firm. The full weight of the firm will back the attorney and you might find it difficult to find an attorney, as many won't want to be involved in suing a fellow professional in their market.

I don't disagree with your fundamental premise about the value of human responsibility, but these professions have been structured to protect their members and the ABA in particular basically functions like a cartel today.